code: def __repr__(self, single_line=True, depth=0):
      ans = ""
      if not single_line and depth > 0:
          ans = "\n" + depth * "\t"
      ans += "(" + self.label
      if self.word is not None:
          ans += " " + self.word
      for subtree in self.subtrees:
          if single_line:
              ans += " "
          ans += subtree.__repr__(single_line, depth + 1)
      ans += ")"
      return ans
  
imports: import logging
  import os
  import pickle
  from collections import Counter
  import numpy
  import torch
  from torch.utils import data
label_desc: Use image node_id 5 for calling the PTBTree obj's underlying member method code with example usage: obj.__repr__(single_line, depth) and returns: ans